1. Field of the Invention
The present invention relates to improved treatment protocol for reducing the degree of proteolysis that occurs in ensiled crops.
2. Description of the Prior Art
Ensiling of forage crops such as alfalfa is a popular method of preserving forage for animal feed in the United States and northern Europe. Proteolysis of the protein content of the forage crop to be ensiled can be in the 40% to 90% range. (Papadopoulos, Y. A, McKersie, B. D., A Comparison of Protein Degradation During Wilting and Ensiling of Six Forage Species, Can. J. Plant Sci., 1983, 63:903-912 and Muck, R. E., Dry Matter Levels on Alfalfa Silage Quality, I. Nitrogen Transformation, Trans. ASAE 1987 30:7-14). The proteins are broken down by this process to produce ammonia, amino acids and small peptides. These materials are poorly utilized in the rumen of the animal being fed and are excreted in animal waste as urea. They thus can add to nonpoint agricultural pollution.
The preservation of forages as silage is an age-old art that has received increasing research interest to decrease animal wastes and improve animal performance through new ensiling practices and feeding management. Inhibition of endogenous plant proteases in silage is difficult. Plant tissues contain numerous proteolytic enzymes that can actively degrade forage protein as soon as the plant cell membranes are lysed or damaged. The large number and variety of proteases has hindered the development of forages that have decreased protein degradation during ensiling. The degradation of plant protein occurs rapidly in the silo with the majority (>75%) happening within the first 48 hours. Because of this, any technique to minimize proteolysis must be initiated at the time of ensiling to have maximized proteolytic inhibition.
Ensiling techniques to reduce proteolysis have focused on either the elimination of proteolytic activity or the alteration of forage proteins to a non-degradable form. Formic acid, bacterial inoculants and heat treatment have been used to enhance forage silage quality. These methods showed a reduction of proteolysis by a factor of 12-28%, with heat treatment being the most effective (Jones et al., Grass Forage Science, 1992, 47; p. 19-27; Waldo, D., The Use of Direct Acidification in Silage Production in Fermentation of Silage—A Review, M. E. McCullough, Editor. 1984, NFIA: West Des Moines, p. 119-149; Charmley et al., Inhibition of Proteolysis at Harvest Using Heat in Alfalfa Silages: Effects on Silage Composition and Digestion by Sheep, J. Anim. Sci., 1990, 68:p. 2846-2854). However none of these methods is cost effective and use of formic acid is caustic to both the machinery and the handler.
The second general approach to reducing proteolysis during ensiling is to alter the proteins so that they resist degradation. Compounds that have been tried include aldehydes (glutaraldehyde and formaldehyde) and tannins. Tannins vary in activity based on the plant producing them and the environmental conditions under which they were made. The mechanism of tannin interaction with proteins is not well understood and hence determining their application rate to a forage like alfalfa is not predictable (Albrecht, K. A and Muck, R. E., Proteolysis in Ensiled Forage Legumes That Vary in Ensilage Concentration, Crop Sci., 1991. 31:p. 464-469). The degree of protection achieved by aldehydes is relatively easy to control but they pose unacceptable health risks.
Presently, no silage treatment can consistently reduce proteolysis during ensiling, leave the forage degradable by the ruminant, pose no health risk, and yet be profitable.
There remains a need for viable and cost-effective alternatives for inhibiting proteolysis in forage crops such as alfalfa and corn during ensiling. If proteolysis could be reduced as little as 25% for alfalfa alone during ensiling, it is estimated that farmers can save 110 million dollars annually.